1. Field of the Invention
The present invention generally relates to a display panel, and more particularly, to a touch display panel and a pixel structure and a multi-sensing structure which are used in the touch display panel.
2. Description of Related Art
In recent years, touch display panels have been widely applied to all sorts of electronic products, for example global positioning systems (GPSs), PDAs, cellular phones and hand-held personal computers, so as to replace conventional input devices (for example keyboards and mice). This drastic change in design not only enhances the friendliness of the human-machine interfaces of the electronic devices, but also provides more space due to the omission of the conventional input devices, so that the user browses information more conveniently.
At this current stage, touch display panels can be categorized, based on the manner in which they are driven and structural designs, into externally-attached resistive touch display panels and internally-embedded resistive touch display panels. For internally-embedded resistive touch display panel technologies, touch functions are directly integrated into manufacturing processes of the panels. An additional layer of touch glass or conductive thin film is not required. Therefore, the internally-embedded resistive touch display panel has advantages of thinner, lighter and better transmittance.
Currently, the internally-embedded resistive touch display panel is usually formed by respectively forming a sensing upper electrode and a sensing lower electrode on the two substrates, and a sensing gap is between the sensing upper electrode and the sensing lower electrode. When a touch operation is performed by applying a pressure on the touch display panel, the sensing upper electrode electrically contacts with the sensing lower electrode. By using the control unit to read out the signals on the upper and lower sensing electrodes, the X and Y coordinates of the position on the touch display panel on which the fingers or objects press against are detected. However, the touch function which is achieved by pressing the touch display panel with the fingers or objects may be affected by the process quality of the touch display panel, so as to influence the touch quality of the touch display panel. For details, the process quality or variation of the touch display panel may lead the touch display panel to have larger or excessively large sensing gap or have smaller or excessively small sensing gap. If the touch display panel has a larger or excessively large sensing gap, a larger touch pressure is required to perform the touch operation, and thereby the touch display panel has lower sensing sensitivity. If the touch display panel has a smaller or excessively small sensing gap sensing gap, an error sensing signal may be generated even the touch operation is not performed, and thereby the touch display panel has excessively high sensing sensitivity.